The present disclosure relates to chip-based probers for high frequency measurements and methods of measuring. More particularly, the present disclosure relates to chip-based probers and methods of using.
The use of test equipment such as vector network analyzers (VNA) is becoming increasingly important during the design of integrated circuit (IC) devices and other electronic components. Here, the test equipment is used for modeling and characterization of a particular device-under-test (DUT).
Measurements of the device-under-test at high frequency require very precise calibration. Unfortunately, the interface devices (e.g., cables, connectors, probers, etc) that interface or connect the device-under-test to the test equipment can make parasitic contributions (e.g., capacitive effects, inductive effects, signal attenuation, etc.) that distort the signal being measured.
In order to account for the parasitic contributions of the interface devices, it is becoming common to perform a calibration that principally moves the measurement reference plane from the test equipment to the device-under-test, effectively bypassing the unwanted effects of the interface devices. One known calibration technique uses a set of electrical standards to move the measurement reference plane to the device-under-test. Here, an open circuit, a short circuit, and 50 Ohm Load standard are measured and the results are used to solve a set of simultaneous equations, whose solution is able to identify the error term needed to move the measurement reference plane.
Generally, the measurement of the device-under-test is carried out using either connectors or radio frequency (RF) probers at an interface of the device-under-test. In both cases, external calibration standards are measured in order to be able to move the reference plane of measurement to the device-under-test from the testing equipment.
Unfortunately, the use of RF probers has several shortcomings. For example, the cost of RF probers can be excessive and the probers themselves are very fragile and can be damaged easily. The RF probers are also limited to a finite number of calibration standards, typically including short, open, and load. Further, the behavior of RF probers can change with frequency and the load can start to look like a short, degrading the calibration. In addition, the large number of times the RF probers is contacted and removed for each of the calibration standards adds uncertainty and leads to calibration inaccuracy as well as reduction in probers lifetime due to the fragile nature of the RF probers.
Moreover, it has been determined that even after calibration with RF probers, some unaccounted parasitic effects in the probers and/or connector can degrade the calibration at high frequency.
Accordingly, there is a continuing need for chip-based probers that overcome, alleviate, and/or mitigate one or more of the aforementioned and other drawbacks and deficiencies of prior art chip-based probers for high frequency measurements.